Ab initio thermodynamic evaluation of Pd atom interaction with CeO 2 surfaces

Adam D. Mayernick, Michael J. Janik

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Palladium supported on ceria is an effective catalytic material for three-way automotive catalysis, catalytic combustion, and solid-oxide fuel cell (SOFC) anodes. The morphology, oxidation state, and particle size of Pd on ceria affect catalytic activity and are a function of experimental conditions. This work utilizes ab initio thermodynamics using density functional theory (DFT) (DFT+U) methods to evaluate the stability of Pd atoms, PdOx species, and small Pd particles in varying configurations on CeO2 (111), (110), and (100) single crystal surfaces. Over specific oxygen partial pressure and temperature ranges, palladium incorporation to form a mixed surface oxide is thermodynamically favorable versus other single Pd atom states on each ceria surface. For example, Pd atoms may incorporate into Ce fluorite lattice positions in a Pd4+ oxidation state on the CeO2 (111) surface. The ceria support shifts the transition between formal Pd oxidation states (Pd 0, Pd2+, Pd4+) relative to bulk palladium and stabilizes certain oxidized palladium species on each surface. We show that temperature, oxygen pressure, and cell potential in a SOFC can influence the stable states of palladium supported on ceria surfaces, providing insight into structural stability during catalytic operation.

Original languageEnglish (US)
Article number084701
JournalJournal of Chemical Physics
Volume131
Issue number8
DOIs
StatePublished - Sep 7 2009

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Cerium compounds
Palladium
palladium
Thermodynamics
Atoms
thermodynamics
evaluation
atoms
solid oxide fuel cells
Solid oxide fuel cells (SOFC)
Oxidation
oxidation
interactions
Density functional theory
Oxygen
density functional theory
cell anodes
Single crystal surfaces
Fluorspar
structural stability

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

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Ab initio thermodynamic evaluation of Pd atom interaction with CeO 2 surfaces. / Mayernick, Adam D.; Janik, Michael J.

In: Journal of Chemical Physics, Vol. 131, No. 8, 084701, 07.09.2009.

Research output: Contribution to journalArticle

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